Docker
Intermediate
Web Container Is Unreachable on Port 80
Browser customers get connection refused on port 80 while the storefront's web container reports Up.
Free simulated incident practice
Find out why the container will not stay healthy.
A successful image build does not tell you whether the application starts, stays running or accepts traffic. Work through Docker incidents that ask you to distinguish those stages. Each exercise starts with a broken simulated system and gives you room to investigate it yourself.
Locate the failing stage
Write down whether the failure appears during the build, when the container starts, or when another service tries to reach it. This keeps a runtime investigation from turning into unrelated changes to the image.
Connect the evidence
Compare the observed container state with its logs and configuration. Explain what each observation rules out. When an application is running but unreachable, examine the path a request must take rather than assuming the process has crashed.
Check the user-visible result
After making a change, verify the application behaviour the incident requires. Record what you changed and why it addresses the symptoms. Use the debrief to compare your investigation with a clearer sequence for the next attempt.
Put the method into practice.
Open a brief to see the symptoms, then launch the incident. The solution is yours to find.
Docker
Beginner
Web Container Exits After Startup
The launch API's container exits with status 0 a moment after every start, so nothing is serving.
Docker
Intermediate
Database Rows Vanish After Restart
Each time the postgres container is recreated, the orders database comes back empty and earlier rows are gone.
Docker
Intermediate
Finance Database Exits After Startup
The finance database container exited ten minutes ago, and every finance API write has failed from that moment on.
Docker
Intermediate
Worker Cannot Resolve Web Backend
The shop worker gets 'bad address' for the web backend on every job, so nothing it processes completes.
Docker
Intermediate
API Image Cannot Be Built
The release-api image build fails at a COPY step, so there is no image to run and nothing answers on the release port 3001.
Docker
Intermediate
Published Frontend Port Refuses Connections
Requests to the frontend on host port 8089 connect and then get an empty reply, although the container is Up and the port is published.
Docker
Intermediate
Web Container Reports Unhealthy
Compose marks the edge web container unhealthy even though its page answers 200, and the release gate that waits on health is blocked.
What kind of lab is this?
FixOps runs simulated systems and a terminal designed for its scenarios. It does not provision a real server or cluster. Use it to rehearse investigation and recovery, and use a real environment when you need unrestricted tooling or production experience.
There is no interview pass guarantee or certification. You can start as a guest in the browser or use the Android app. If the concepts feel unfamiliar, work through a learning track before trying another incident.
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